Translator’s Note:I have added background information to this
blog entry written by Master Zhao Ming Wang.As far as I can tell, Niu Jin Bao (1915-1988) respected Du Xinwu to such
an extent that he wanted to transmit Zhao Bichen’s lineage to him.This can be read in my published article
here: In Memory of My Father Niu Jin Bao (牛金宝) By Niu Sheng Xian (牛胜先) ACW 11.9.15

(Right) Du Xinwu (1869-1953) was a famous martial artist who
once served as Sun Yat-sen’s bodyguard.He is famous for Zi Ran Men (自然門), or ‘Natural Gate’ style of
Daoist martial arts, which he learned from Master Xu [徐] (who
is described in the Chinese literature as a ‘dwarf’).